The present invention relates to a plasma addressing display device having a flat panel structure in which a display cell and a plasma cell are stacked to each other, and particularly to an electrode structure in each of discharge channels formed in the plasma cell.
A plasma addressing display device configured to use a plasma cell for addressing a display cell has been disclosed, for example, in Japanese Patent Laid-open No. Hei 4-265931.
As shown in FIG. 1, the plasma addressing display device disclosed in the above document has a flat panel structure including a display cell 1, a plasma cell 2, and a common intermediate substrate 3 interposed therebetween.
The plasma cell 2 has a lower substrate 8 joined to the intermediate substrate 3 with a specific gap kept therebetween. An ionizable gas is enclosed in the gap therebetween.
Stripe-shaped discharge electrodes 9A and 9K are alternately formed on the inner surface of the lower substrate 8. The discharge electrode 9A having a wide width functions as an anode, and the discharge electrode 9K having a narrow width functions as a cathode. These discharge electrodes 9A and 9K are formed of a metal thin film.
Barrier ribs 10 are each formed on the anode side discharge electrode 9A, to thereby divide a space filled with the ionizable gas into discharge channels 12.
Each cathode side discharge electrode 9K is positioned between the adjacent ones of the barrier ribs 10.
The barrier ribs 10 can be formed by overlappingly coating the discharge electrodes 9A with typically glass paste by a screen printing process. The tops of the barrier ribs 10 are in contact with the underside of the intermediate substrate 3.
One discharge channel 12 includes one discharge electrode 9K functioning as the cathode and two discharge electrodes 9A functioning as the anodes disposed on both sides of the discharge electrode 9K. The discharge channel 12 generates a plasma discharge between the cathode side discharge electrode 9K and the anode side discharge electrodes 9A.
The intermediate substrate 3 is jointed to the lower substrate 8 by means of glass frit 11 or the like.
The display cell 1 has a transparent upper substrate 4. The upper substrate 4 is stuck on the intermediate substrate 3 with a specific gap kept therebetween by means of a sealing material 6 or the like, and the gap is filled with an electro-optic material such as a liquid crystal 7. Signal electrodes 5 are formed on the inner surface of the upper substrate 4. The signal electrodes 5 cross the stripe-shaped discharge channels 12 at right angles. Pixels are defined in a matrix pattern at portions where the signal electrodes 5 cross the discharge channels 12.
In the plasma addressing display device having the above-described configuration, the display drive is performed by scanning rows of the discharge channels 12 on the plasma cell 2 side in such a manner as to switch them in line-sequence and applying image signals to columns of the signal electrodes 5 on the display cell 1 side in synchronization with the scanning of the discharge channels 12. When a plasma discharge is generated in each discharge channel 12, the interior of the discharge channel 12 becomes a substantially uniformly anode potential, to effect the pixel selection for each row. That is to say, the discharge channel 12 functions as a sampling switch. When an image signal is applied to each pixel in the state in which the plasma sampling switch is made conductive, sampling for the pixel is performed, to thereby control the turn-on/off of the pixel. Even after the plasma sampling switch becomes non-conductive, the image signal remains held in the pixel.
FIG. 2 is a typical perspective view showing an electrode structure and a barrier rib structure on the lower substrate 8 shown in FIG. 1. The anode side discharge electrodes 9A and the cathode side discharge electrodes 9K, patterned into the stripe-shapes, are alternately arranged. These discharge electrodes are formed by depositing a metal thin film of aluminum or the like by sputtering or vacuum vapor-deposition and selectively etching the metal thin film into stripe shapes. The barrier ribs 10 are formed on the anode side discharge electrodes 9A. The width of the barrier rib 10 is typically 160 .mu.m which is narrower than the width (typically, 470 .mu.m) of the anode side discharge electrode 9A. The barrier ribs 10 can be formed by overlappingly coating the discharge electrodes 9A with dielectric paste such as glass paste and being baked. In addition, the width of the cathode side discharge electrode 9K is typically about 80 .mu.m, and the lower substrate 8 is formed of typically a glass plate.
In the related art structure shown in FIG. 2, the barrier ribs 10 composed of the baked body of glass paste are formed on the broad discharge electrodes 9A formed of a metal thin film. However, the adhesion between a metal thin film and a baked body of glass paste is generally weak. Accordingly, the related art structure causes a problem that the barrier ribs 10 may be peeled or damaged during the manufacturing process. To solve the problem, it may be considered to change the material of the discharge electrodes 9A from the metal thin film of aluminum or the like into a baked body of conductive paste for improving the adhesion with the barrier ribs 10 made from the baked body of insulating paste such as glass paste; however, such a method has the following inconvenience. At present, only nickel paste containing nickel particles can be practically used as the conductive paste; however, if the discharge electrodes are made from the nickel paste, vapor of mercury must be previously contained in a discharge gas for preventing wear of nickel due to plasma discharge, giving rise to a problem in terms of both safety of products and environmental protection.